Sixers center Andrew Bynum underwent bilateral arthroscopic surgery on his knees Tuesday. The procedure was performed by Dr. David Altchek with the Hospital for Special Surgery in New York.

Bynum will begin non-weight bearing physical therapy on Friday for approximately three weeks. He will spend an additional three weeks on crutches after the physical therapy.

Bynum suffered a bone bruise in his right knee in September while working out and injured his left knee bowling in November. He was unable to practice with the team until his lone workout in February left him with pain and swelling.

The Sixers acquired Bynum in a four-team blockbuster trade that sent Andre Iguodala to Denver and first-round picks Nik Vucevic and Moe Harkless to Orlando.